The Tissue and Pathology Core will collect tissue samples from human skin tumor specimens, for use in the SPORE projects and pilots, and for the use of other qualified investigators as determined by the Tissue and Resource Allocation Committee in accordance with the SPORE guidelines. Procedures have been developed for procurement, processing, storage, quality control, gross and microscopic pathological evaluation, and allocation of samples that will ensure optimal utilization and distribution of the limited tissue samples. In addition, the Core will provide expertise to the Projects for the development of in situ imaging and microdissection techniques in sections of human skin tumors for use in the projects, and for the development of techniques for expert pathological interpretation of histological data, using immunohistochemical methods with a variety of antigen retrieval techniques in situ hybridization using oligonucleotide probes, laser cutting microdissection, and nucleic acid amplification techniques.